1. Field of the Invention
The invention relates to an assembly and method for evaluating the performance and effectiveness of anti-fog products applied to eyewear lenses.
2. Description of the Prior Art
It is known to test ski goggles to measure the time for light transmission though the goggle to decrease. As condensation forms on the inner surfaces of the goggles, and scatters light passed therethrough, the light transmission through the goggles decreases.
A current test method includes placing eyewear goggles lenses horizontally on a heated water bath. A collimated laser beam is passed through the lens and a photosensor is used to measure the time for the light transmission to decrease by a selected degree as condensation forms on the inner surfaces of the lenses and scatters the light.
The test has been found wanting inasmuch as real eyewear is worn in a generally vertical position on a user's face, and the test does not account for airflow between the user's face and the eyewear frame. Further, the test does not factor in the fact that other headwear, such as hats or helmets, can interfere with airflow, and the test does not capture the dynamic nature of the fogging event.
Accordingly, there is a need for an improved test for the efficacy of anti-fog coatings on eyewear lenses.